1. Field of the Invention
The present invention relates to a gate valve capable of opening, closing, and sealing an opening portion of a vacuum process chamber used in for example the manufacturing process of a semiconductor device.
The present invention also relates to a cylinder apparatus suitable for driving a gate valve etc., more particularly relates to a cylinder apparatus suitable for driving a gate valve capable of opening, closing, and sealing an opening portion of a vacuum process chamber.
2. Description of the Related Art
In a dry etching step, sputtering step, epitaxial wafer forming step, etc. in the manufacturing process of a semiconductor device, use has been made for example of a vacuum process apparatus of a multi-chamber structure comprising a plurality of vacuum process chambers connected with each other as shown in FIG. 1.
In the vacuum process apparatus 101 illustrated in FIG. 1, a plurality of vacuum process chambers 105 for performing various processing are connected to the outer circumference of a transport chamber 102 to and from which a wafer W is transported. Movement of the wafer W between the transport chamber 102 and each vacuum process chamber 105 is carried out through a gate G. The opening, closing, and sealing of the gate G are carried out by a not illustrated gate valve.
In the illustrated vacuum process apparatus 101, the wafer W is transported into the transport chamber 102 by a transport device (not illustrated) through an inlet and outlet port 103 of an inlet and outlet path 104 and held by a vacuum transport robot 107 provided in the transport chamber 102. When the wafer W is held by the vacuum transport robot 107, the inlet and outlet port 103 is closed and the interior of the transport chamber 102 is evacuated. At this time, the gate valves are made to seal the gates G. When the evacuation of the transport chamber 102 is completed, the gate valves are driven to open the gates G. and the wafer W is transported to a predetermined vacuum process chamber 105 by the vacuum transport robot 107. In order to perform processing such as dry etching in the vacuum process chamber, the gate valves are driven to close the gates G, and predetermined processing such as dry etching is carried out on the wafer W. When the predetermined processing of the wafer W is completed, the gate valves are driven to open the gates G, and the wafer W is taken out of the vacuum process chamber 105 again by the vacuum transport robot 107 and automatically taken to the outside of the vacuum process apparatus 101 through the inlet and outlet port 103.
As a gate valve capable of opening, closing, and sealing the gate G in the vacuum process apparatus 101 as described above, for example a gate valve having a cross-sectional structure shown in FIG. 2 and FIG. 3 has been known.
In FIG. 2, a transport chamber 202 corresponding to the transport chamber 102 of FIG. 1 is connected with a vacuum process chamber 203 corresponding to the vacuum process chamber 105 of FIG. 1 through the gate G. The opening and closing of this gate G are carried out by a gate valve 201. The gate valve 201 has a valve body 205 performing opening, closing, and sealing of the gate G, a valve rod 206 to one end portion of which this valve body 205 is fixed, which is held so that it can move straight, and which can be inclined about a predetermined axis 208, a seal bellows 207 for sealing between the transport chamber 202 and the valve rod 206, and a not illustrated driving means for moving the valve rod 206 straight and inclining it.
The gate valve 201 illustrated in FIG. 2 is shown in a state where the gate G is opened. In order to close and then seal the gate G, as shown in FIG. 3, the valve rod 206 is moved straight and then moved up to a position at which the valve body 205 closes the gate G and the valve rod 206 is inclined about the axis 208. As a result, the valve body 205 presses against an O-ring 204 provided at the outer circumference of the gate G and seals the gate G.
In the gate valve 201 having the above structure, it is required that the sealing property when sealing the gate G by the valve body 205 be good, that there be no sliding part generating particles due to friction with the valve body 205 and the valve rod 206 provided in the transport chamber 202, that the movement of the valve body 205 by the not illustrated driving means be smooth and possible at a high speed, that the force for inclining the valve body 205 for crushing the O-ring 204 in order to secure a sufficient seal be sufficient, that the structure be simple and inexpensive, and so on.
In the gate valve 201 having the above structure, however, in order to perform the straight movement and inclination of the valve rod 206, sufficiently obtain a force for inclining the valve body 205, and operate the valve body 205 smoothly and at a high speed, the structure of the driving means for driving the valve rod 206 becomes complex. As a result, there are the disadvantages that the number of parts becomes large and the gate valve 201 becomes expensive.
A cylinder driven by compressed air (hereinafter referred to as an air cylinder) is usually used for driving the valve rod 206 of the gate valve 201 of the above structure. When an air cylinder is used for driving the valve rod 206, when the valve rod 206 is inclined so as to press against the O-ring 204, a moment will act upon the air cylinder from the valve rod 206 as a reaction force. However, usually, an air cylinder is not structured to be able to support a large moment applied to a piston rod. An air cylinder not structured to be able to support a large moment applied to a piston rod has the disadvantage that if the moment is repeatedly applied to the piston rod, wear and fatigue are apt to occur in constituent parts such as the piston, cylinder, and sealing member and there is insufficient durability with respect to moment.
An object of the present invention is to provide a gate valve which is simplified in structure and inexpensive, is smooth and high speed in movement of the valve body, is strong in the force for inclining the valve body, and is improved in the sealing property of the opening portion.
Another object of the present invention is to provide a cylinder apparatus improving the durability with respect to the moment acting upon the piston rod.
Still another object of the present invention is to provide a cylinder apparatus suitable for driving a gate valve.
According to a first aspect of the invention, there is provided a gate valve of the following configuration. The gate valve has a valve body provided in a sealed chamber, capable of opening and closing an opening portion of the sealed chamber, and capable of sealing the opening portion by inclination with respect to the opening portion; a valve rod to one end portion of which the valve body is fixed, held so that it can move straight and incline, provided so as to project from an interior of the sealed chamber to an outside of the sealed chamber, and provided so as to hold the sealed state of the sealed chamber by a sealing means; an inclination mechanism connected to the valve rod and inclining the valve rod; and a driving means connected to the valve rod via the inclination mechanism and supplying a drive force required for the straight movement and inclination of the valve rod. The inclination mechanism has a roller rotatably provided on the other end of the valve rod; a roller receiving member formed with a first holding portion provided facing the other end portion of the valve rod, capable of holding the roller, and holding the roller when the valve rod moves straight in a direction opening and closing the opening portion, with an inclined surface continuous with the first holding portion, capable of engaging with the roller, and engaging with the roller so as to make the valve rod incline, and with a second holding portion continuous with the inclined surface, capable of holding the roller, and holding the roller when the valve rod is inclined up to a predetermined angle and moved straight by the driving means; and a limiting means for limiting the straight movement of the valve rod at a predetermined position at which the valve body closes the opening portion and releasing the holding state of the roller receiving member of the roller by the first holding portion. When the roller receiving member is moved straight in a direction closing the opening portion from a state where the valve body opens the opening portion, the roller receiving member moves the valve rod straight to the predetermined position in a state where the roller is held by the first holding portion. When the roller receiving member is further moved straight, the holding state of the roller by the first holding portion is released, the roller is engaged with the inclined surface, and the valve rod inclines to seal the opening portion. When the valve rod is inclined up to a predetermined angle, the roller is held by the second holding portion.
In the gate valve of this aspect of present invention, when the roller receiving member is moved straight in a direction closing the opening portion of the sealed chamber by the driving means, the valve rod moves straight in a state of the first holding portion holding the roller, and when the valve rod reaches the predetermined position, the movement of the valve rod is limited and the valve body closes the opening portion. When the roller receiving member moves further straight, the valve rod does not move and only the roller receiving member moves, the state where the roller is held at the first holding portion is released, and the roller rolls on the inclined surface while rotating, whereby the valve rod is inclined. At this time, the straight movement force of the roller receiving member is amplified by a wedge effect of the inclined surface, and the inclination force of the valve body is amplified. By this, the sealing of the opening portion by the valve body is carried out well. When the valve rod is inclined by a predetermined angle by a further straight movement of the roller receiving member, the roller is in a state where it is held at the second holding portion of the roller receiving member, and the sealing operation of the opening portion by the valve body is completed.
According to a second aspect of the present invention, a gate valve having the following configuration is provided. The gate valve has a valve body provided in a sealed chamber, capable of opening and closing an opening portion of the sealed chamber and then sealing the opening portion by inclining with respect to the opening portion; a valve rod to one end portion of which the valve body is fixed, held so that it can move straight and incline, provided so as to project from an interior of the sealed chamber to an outside of the sealed chamber, and provided so as to hold the sealed state of the sealed chamber by a sealing means; an inclination mechanism connected to the valve rod and inclining the valve rod; a driving means connected to the valve rod via the inclination mechanism and supplying a drive force required for the straight movement and inclination of the valve rod; and a holding means for holding the valve rod and the inclination mechanism moved straight by the driving means so that they can freely move in a horizontal direction.
Preferably, the holding means has a rail horizontally arranged along the direction of straight movement of the valve rod and first and second movement members moveably provided on the rail; the valve rod is held by the first movement member so that it can freely incline; and the inclination mechanism is held by the second movement member.
According to a third aspect of the present invention, there is provided a gate valve of the following configuration. The gate valve has a valve body provided in a sealed chamber, capable of opening and closing an opening portion of the sealed chamber, and capable of sealing the opening portion by inclination with respect to the opening portion; a valve rod to one end portion of which the valve body is fixed, held so that it can move straight and incline, and provided so as to project from an interior of the sealed chamber to an outside of the sealed chamber and hold the sealed state of the sealed chamber by a sealing means; an inclination mechanism connected to the valve rod and inclining the valve rod; a driving means connected to the valve rod via the inclination mechanism and supplying a drive force required for the straight movement and inclination of the valve rod; and a lock mechanism for holding the sealed state of the opening portion by the valve body. The driving means is a cylinder apparatus having a piston rod, one end of which is connected to the inclination mechanism via a connection plate, a piston fixed to the other end of the piston rod, and a cylinder unit for accommodating this piston inside it. The lock mechanism has a lock plate which is fixed to the connection plate along the drive direction of the piston rod, on one surface of which an inclined guide surface being formed, and in which a lock hole is formed in a direction perpendicular to the drive direction of the piston rod, a small cylinder provided at a predetermined position with respect to the cylinder apparatus, and a lock piston accommodated in the small cylinder, on one end of which a lock pin capable of being fit in the lock hole by being guided by the inclined guide surface is formed, and the other end of which is biased by a resilient member so as to project to a position at which the lock pin can abut against one surface of the lock use plate from the small cylinder. A supply port for supplying a compressed fluid for driving the lock piston in a direction in which the lock pin is accommodated in the small cylinder into the small cylinder is formed in the small cylinder. The supply port is communicated with a supply path for supplying the driving medium for driving the valve body in an opening direction into the cylinder unit of the cylinder apparatus. When the cylinder apparatus is driven in a direction sealing the opening portion by the valve body, the lock pin is guided by the inclined guide surface of the lock use plate and fit in the lock use hole, the movement of the connection plate is locked, and the sealed state by the valve body is held. When the cylinder apparatus is driven in a direction opening the; opening portion by the valve body, the compressed fluid is supplied into the small cylinder through the supply path to the cylinder apparatus, and the engagement between the lock pin and the lock hole is released.
According to a fourth aspect of the present invention, there is provided a cylinder apparatus having a piston rod, a piston fixed on one end of this piston rod, and a cylinder unit for accommodating this piston inside it so that it can slide; driving the piston by a driving medium supplied to the internal portion of the cylinder unit and capable of moving the piston rod straight; and further having a support mechanism capable of supporting the piston rod against a moment acting upon the piston rod.
Preferably, the cylinder apparatus is used for driving a gate valve having a mechanism capable of opening and closing an opening portion of a sealed chamber by straight movement of the valve body and then capable of sealing the opening portion by the inclination of the valve body; and the support mechanism can support the piston rod against a reaction force moment acting upon the piston rod at the time of inclination of the valve body.
More preferably, the support mechanism of the cylinder apparatus has a support shaft formed at a front end of the piston and a support hole into which the support shaft can be inserted formed at a position facing the piston inside the cylinder unit.
Preferably, a bushing fitting with the support shaft is placed in the support hole.
More preferably, the support shaft is integrally formed with the piston rod.